Who was the scientist that said the earth was flat?

It is a common knowledge that the world is round. I never read or heard anybody teach that the world is flat.

A very very long time ago, the world once was thought to be flat. The horizon that we see now, people use to think that when you got to that point you would fall off the edge of the world. Not until boats and navigation came into fruition, the then thought "brave" explorers, set out to discover the edge of the world. It wasnt until they started sailing familiar waters that the theory of a round world came to be. Interesting huh?